One way around the problem is Experian QAS Pro software. Its parent company, Experian, is the same one that has brought you credit reports for the past few decades.

QAS is an address-capture utility that offers a window into the U.S. Postal Service’s address file of about 155 million addresses. The software also can be configured for other countries. I noticed on the QAS Web site for Great Britain (www.qas.co.uk) that the company configures the software for the Royal Mail postcode address file.

If you buy the software, a staff member from QAS will come to your office and configure the software to work with whatever existing constituent management database you use. QAS will send you an update every two months. It will work with Oracle, SAP, Microsoft SQL Server and Siebel databases, among others. It won’t run on Macs, but it will work with Unix and most kinds of Windows (95/98/ME/XP and NT/2000/2003). It’s also available in client-server or local versions.

QAS comes on two disks that took up about a gigabyte on my Dell Optiplex GX 280 with an 3.20 GHz Intel CPU running Windows XP. The company uses proprietary compression techniques to keep the storage space low.

The software loads four main sections: a configuration utility, a data checker, QuickAddress Pro (the main data entry window) and a link to a support site.

QAS came with easy-to-follow notes on how to use hot keys to reduce keystrokes. Alt-Q, for example, pops up the QuickAddress Pro window and Ctrl-N starts a new search. It lets you drill down through the database so that you only have to select addresses from a list, down to the apartment or suite level, going from the more general, such as ZIP code or city name, to the more specific.

The software also corrects you as you type. If you make a mistake or put in a nonexistent address, the font automatically turns red.

I typed what I thought would be an imaginary address: Santa Claus, North Pole. But the font did not turn red. Guess what, Virginia? There really is a Santa Claus, and he lives at 325 S Santa Claus Lane, North Pole, Alaska 99705-9900.

I found my grandmother’s house in Fort Smith, Ark., in three clicks. Clicking on “Accept” will load the address into the address entry program you are using.

One problem government agencies have in managing their address lists is that people often leave off their apartment numbers. As an apartment dweller myself, I can attest that I see a lot of abandoned letters in the lobby addressed to John Smith, 1234 Tower Street, Bethesda, Md. This is like John Smith wanting to give the impression he owns the whole building and not just a modest one-bedroom apartment.

Quick Address Pro lets you know that John Smith has given you incomplete information by showing you the available apartment numbers associated with that address.

The package also comes with a sheet of exercises to try out. I tried to guess the city that correlated to the ZIP code but was usually not close. When I worked on a USPS contract, some of the older postal workers would play a ZIP code game where somebody would holler out a ZIP code, and somebody else would name the city. The only ZIP code cities I knew were 90210, my home, work and a few others.

One of the suggested exercises that came with QAS was to type in 300 Wilkins Ave. with a ZIP code of 23868. I knew there’s a Wilkins Ave. in Baltimore, so I tried to put in Baltimore as a city name. No luck: The letters turned bright red. It turns out 23868 is the ZIP code for Lawrenceville, Va.

The hands-on support of Experian QAS staff members was a real plus. They even called me a week or so after I installed the software to see if it was running OK or if I had any questions.

Experian QAS is a serious address package for serious work — motor vehicle departments, unemployment offices, tax administration offices and courts — people who need to find your real, current address without delay.